What Determines Puppy Litter Size?

Litter size in dogs is difficult to predict, especially by non-experts without the proper tools, because it's influenced by many different factors. Regardless of what you may hear, you can't tell how many pups she's carrying based on how she looks or behaves during her pregnancy. Because knowing how roughly many pups to expect is important to your dog's health during pregnancy and birth, it's important to see your vet to confirm your dog's pregnancy and to estimate her litter size. However, what we can offer are a few facts regarding puppy litter size in general.

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What Is Normal?

Litter size varies tremendously from dog to dog, with smaller dogs producing smaller litters in most cases. Some dogs may give birth to a single puppy, while other dogs may bear 17 puppies or more, according to PetPlace. If your dog eats and behaves normally during pregnancy, no complications develop and the puppies are developing normally inside the uterus, the litter size is considered normal.

Factors Influencing Litter Size

Many factors affect the number of puppies in a litter. Older and younger dogs tend to have smaller litters, while dogs aged 3 to 4 years tend to produce the largest litters. Breed also plays a significant role in litter size, with larger breeds producing a greater number of puppies. First-time mothers are more likely to give birth to one or two puppies, while experienced mothers often have three or more. Inbreeding, nutrition, the age of the father and certain health conditions can also increase or decrease litter size.

Increasing Litter Size

Breeders may attempt to increase litter size by closely monitoring ovulation. Because ovulated eggs are not fully mature for 48 hours, knowing exactly when to breed is essential for a large litter size. Artificial insemination may seem like an easy way to get the timing just right, but a significant number of sperm usually die between harvest and insemination, which tends to reduce litter size instead of increasing it.

Determining Litter Size Before Birth

A normal gestation period in dogs is from 58 to 68 days. It is rarely possible to feel individual puppies before the pregnancy is half over. Even later in pregnancy, determining the number of puppies with any accuracy is difficult without specialized equipment. An abdominal ultrasound can estimate litter size after the third week of pregnancy or later, and a radiograph can provide a count of the number of skeletons inside the mother's uterus.

Large Litter Complications

Larger litters may put your dog at greater risk for complications during pregnancy and birth. Giving birth to multiple puppies can be exhausting, which can slow or even stop uterine contractions. Additionally, the risk of bleeding and other complications increases with each puppy. Larger litters are also more difficult to nurse, putting Mom at risk for dehydration and exhaustion and the puppies at risk for malnutrition and failure to grow.

By Sandra Ketcham


References

PetPlace: Pregnancy in Dogs
Royal Canin: Litter Size in Dogs
Perfect Puppy Care: Canine Litter Size

Kennel Spotlight: Litter Size and Singleton [PDF]
Find a Vet: How to Help Your Dog Give Birth

About the Author
Sandra Ketcham has nearly two decades of experience writing and editing for major websites and magazines. Her work appears in numerous web and print publications, including "The Atlanta Journal-Constitution," "The Tampa Bay Times," Visit Florida, "USA Today," AOL's Gadling and "Kraze Magazine."